Field of the Invention
The present disclosure relates to a method of manufacturing a metal separator for a fuel cell.
Discussion of the Background
For example, a solid polymer electrolyte membrane formed of a polymer ion exchange membrane is used for a solid polymer electrolyte fuel cell. The fuel cell has a power generation cell in which a membrane electrode assembly (MEA) is sandwiched between separators (bipolar plates), the membrane electrode assembly being formed by disposing an anode-side electrode and a cathode-side electrode including an electrode catalyst and a porous carbon on both sides of the solid polymer electrolyte membrane, respectively. A fuel cell including stacked layers of a plurality of power generation cells is used, for example, as an in-vehicle fuel cell stack.
In the fuel cell, a passage for passing a fuel gas (hereinafter also referred to as a reactant gas) is formed in the surface of the separator that faces the anode-side electrode, while a passage for passing an oxidant gas (hereinafter also referred to as a reactant gas) is formed in the surface of the separator that faces the cathode-side electrode. In addition, a passage for passing a cooling medium between separators is formed for each power generation cell or for a predetermined number of power generation cells.
Thus, it is necessary to securely seal between the passages so that a fuel gas, an oxidant gas, and a cooling medium are not mixed with each other, and also necessary to prevent intrusion of a foreign substance into the passages and a short circuit between the separators. For this reason, a metal separator in which a sealing member is integrally molded on both sides of the outer peripheral edge of a metal plate is used, for example.
For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-305006, there is known a fuel cell in which the above type of metal separator is used, and an insulating member is provided around the periphery of each communication hole formed in the separator. Specifically, as illustrated in FIG. 10, a separator 1 and a membrane electrode assembly (not shown) are stacked alternately, and a communication hole 2 is formed in the separator 1 through in the stacking direction, for passing a reactant gas and a cooling medium.
The separator 1 is provided with a metal plate 3 composed of a stainless steel plate material or the like, and a seal member 4 is integrally molded with the metal plate 3. The separator 1 is provided with a circular insulating member 5 which surrounds the communication hole 2.